<Emphasis Type="Italic">In Vitro</Emphasis> Comparison of the Effect of Stent Configuration on Wall Shear Stress Using Time-resolved Particle Image Velocimetry

Time resolved particle image velocimetry was used to measure wall shear stress (WSS) and oscillatory shear index (OSI) within a 3.0 mm diameter compliant vessel model implanted with an Abbott Vascular XIENCE V^® stent in five configurations: baseline, over-expanded, increased vessel diameter, two overlapped stents, and increased stent length. Flow through unstented vessels was also tested for comparison. Flow conditions featured a realistic coronary pressure-flow offset and reversal at average flow rates corresponding to resting (Re = 160, f = 70 bpm) and exercise conditions (Re = 300, f = 120 bpm). Comparisons revealed that the WSS was similar for all cases behind the first strut and downstream of the device, indicating that changes in configuration have little effect downstream. However, there were notable differences within each stent revealing reduced WSS values for all cases due to the stent-imposed expansion of the vessel wall (0.20–9.29 dynes/cm² for Re = 160 and d = 3.0 mm). Over-expanding the stent with a second balloon affected the alignment of the stent geometry, and led to higher WSS at the inlet and lower values at mid-stent. The overlapped stents showed disturbed flow and a WSS deficit region downstream of the overlapped region. Analysis of the longer stent showed that the WSS within the vessel recovers with distance. An overall correlation was noted between decreased WSS values and elevated OSI. Results of this study are important because decreased WSS has been implicated in endothelial cell changes and increased restenosis, and clinical research has shown that a link exists between deployment configurations and negative patient outcomes.     

Specialisation and specialist education in prosthetic dentistry in Europe

This presentation reports on the results of a meeting of prosthodontists from selected European countries. The aim of the meeting was to analyse and promote specialisation and specialist education in Prosthetic Dentistry in Europe. Representatives for Europe were selected from the European Prosthodontic Association (EPA) board, the Education and Research Committee of International College of Prosthodontists (ICP), countries with a legally recognised speciality, countries without a recognised speciality but organised training programmes and countries with neither of these situations. Data about specialisation and specialist training in Prosthodontics in Europe was scrutinised and discussed. The programmes for countries with specialist training had relatively similar content, mostly of three years duration. There was strong agreement that a recognised speciality raises the level of care within the discipline for both specialists and non-specialists. In several of the countries where a speciality had been introduced it had been initiated by pressure from public health planning authorities. The conclusions are that from a professional viewpoint an advancement of the speciality over Europe would develop the discipline, improve oral health planning and quality of patient care. A working group for harmonisation was recommended.     

Expanding the scales: The multiple roles of MCH in regulating energy balance and other biological functions

Melanin-concentrating hormone (MCH) is a cyclic peptide originally identified as a 17-amino-acid circulating hormone in teleost fish, where it is secreted by the pituitary in response to stress and environmental stimuli. In fish, MCH lightens skin color by stimulating aggregation of melanosomes, pigment-containing granules in melanophores, cells of neuroectodermal origin found in fish scales. Although the peptide structure between fish and mammals is highly conserved, in mammals, MCH has no demonstrable effects on pigmentation; instead, based on a series of pharmacological and genetic experiments, MCH has emerged as a critical hypothalamic regulator of energy homeostasis, having effects on both feeding behavior and energy expenditure.     

Monitoring plasma voriconazole levels following intravenous administration in critically ill patients: an observational study

Data relating to the pharmacokinetics of voriconazole in critically ill patients are lacking. A prospective observational study was conducted on 18 non-consecutive critically ill patients aged 24–97 years, comprising 12 patients with normal renal function (NRF) [creatinine clearance (CL_Cr) ≥60 mL/min] and 6 patients with moderate renal impairment (MRI) (CL_Cr 40–55 mL/min), administered voriconazole intravenously (6 mg/kg loading dose and 3–4 mg/kg twice daily thereafter) in order to determine the suitability of these doses in this patient population. Steady-state blood levels were monitored and liver and renal function were recorded throughout treatment. Large variability in patient plasma levels was observed, ranging from 37% at ≤1 mg/L (minimum inhibitory concentration at which, for most fungal pathogens, 90% of isolates are susceptible) to 19% at >5.5 mg/L. Moreover, maintaining trough concentrations above clinical breakpoints was not consistently achieved because 16/30 (53%) were ≤1 mg/L. In a few MRI patients, average concentrations were found to be significantly different compared with those of NRF patients administered the same dose, however this difference was not noted in pharmacokinetic parameters following dose normalisation. None of the patients experienced deterioration in renal or liver function. Recommended voriconazole doses are inadequate to achieve drug concentrations >1 μg/mL over the entire dosing interval in some critically ill patients.     

Reversal of tetraplegia in a patient with haematogenous cervical epidural abscess

Pyogenic haematogenous cervical epidural abscess complicated by tetraplegia is an uncommon entity, but its clinical importance overshadows its rarity. Predisposing risk factors for spinal epidural abscess include diabetes, intravenous drug abuse, liver disease, renal failure, malignancy, HIV, infection elsewhere, rheumatoid conditions, trauma and a number of spinal interventions. Lack of recovery and death are much more frequent when complete paralysis exists since more than 24 to 48 hours. Most authors combine decompressive laminectomy and antibiotics. Anterior decompression and needle aspiration are rarely used, the former more specifically in case of anterior abscess formation. A high index of suspicion along with reliance on gadolinium-enhanced MRI is essential to diagnose the pathology and institute appropriate treatment on an individual basis. The authors report on a diabetic male patient who developed a cervical epidural abscess with tetraplegia after dental extraction. He was treated within six hours by one stage anterior/posterior decompression and fusion, with complete recovery.     

Causal Diagram Techniques for Urologic Oncology Research

Large quantities of data are now available to medical researchers; however, observational studies are plagued by bias and confounding. Additionally, much of this research only speculates on variable associations, leaving prospective randomized clinical trials as the sole purveyors of claims about causal relations between variables. There has been a growing movement of causal inference that uses new techniques to investigate causality using observational data. These techniques include the implementation of directed acyclic graphs, which allow researchers to explicitly and reproducibly define the causal relationships between study variables, thus making statistical analysis more robust. Directed acyclic graphs further allow researchers to identify confounding and other sources of bias and to discover causal effects among complex networks of variables. This review aims to introduce these techniques to the general urology and urologic oncology research communities in order to provide a basic understanding of causal inference and analysis and call for integration of these practices more generally in research methodology.     

Recovery of shoulder abduction in traumatic brachial plexus palsy: a systematic review and meta-analysis of nerve transfer versus nerve graft

Brachial plexus palsy is a surgically manageable condition. Re-animating the shoulder is a high priority for restoring upper extremity function. Methods for reinnervating injured nerves include the transfer of a healthy nerve or fascicle distal to the site of injury, or grafting a healthy sensory nerve to restore motor function. Studies aiming to compare these two techniques for restoring shoulder abduction have yielded conflicting results. We conducted a systematic review and meta-analysis following the PRISMA guidelines. We reviewed the PubMed database for studies comparing nerve transfer and nerve grafting for shoulder abduction published by December 2018. Outcomes using the Medical Research Scale (MRC) for muscle strength were assessed using a random effects model meta-analysis. Five studies comprising a total of 212 patients (n = 158, nerve transfer; n = 54, nerve grafts) were used for the analysis. The rate of functional recovery of shoulder function was slightly better for nerve transfer (n = 114/158, 72%) than for nerve graft patients (n = 36/54, 67%). However, this was not statistically significant (OR 1.34, 95% CI 0.27–6.72, I2 = 62.9%). Nerve transfer and grafting are similarly effective in terms of shoulder abduction. Future prospective studies are needed to validate our results and identify the optimal shoulder re-animation strategy in patients with brachial plexus injuries.     

A short time interval between the neurologic index event and carotid endarterectomy is not a risk factor for carotid surgery

Objective

Current guidelines recommend that carotid endarterectomy (CEA) be performed as early as possible after the neurologic index event in patients with 50% to 99% carotid artery stenosis. However, recent registry data showed that patients treated ≤48 hours had a significantly increased perioperative risk. Therefore, the aim of this single-center study was to determine the effect of the time interval between the neurologic index event and CEA on the periprocedural complication rate at our institution.